On 2002-01-11 1:07, "ext Graham Klyne" <Graham.Klyne@MIMEsweeper.com> wrote:
> One thing that I can imagine doing, but something that I think is beyond
>
> our current charter, is to have a way of relating an rdf:Statement
> instance
> to a truth value; i.e. a way of saying that an rdf:Statement
> corresponds
> to an asserted triple. A simple example might be similar to the style
> of
> RDFS-entailment, such that:
>
> s a rdf:Statement ;
> rdf:predicate pred ;
> rdf:subject sub ;
> rdf:object obj ;
> rdf:hasValue rdf:True .
>
> statement-entails:
>
> sub pred obj .
>
> (I don't think this particular approach is especially useful; e.g. for
> provenance we'd want to be able to make the entailment also depend in
> some
> way on expressed trust in the source of the statement, but I think
> that's
> still an area for experimentation.)
This is precisely what I had suggested some time ago with my X proposal,
which also takes into account issues such as trust/authority, as well
as source, authentication, scope, and all other qualifications of
statements. It's just an issue of (a) having only one representation
for statements and (b) shifting matters of assertion, trust, etc. to
a suitable ontology (or ontologies) for qualifying statements. E.g.
s a rdf:Statement ;
rdf:predicate pred ;
rdf:subject sub ;
rdf:object obj ;
rdf:assertedBy <auth://abc.com/john.doe> ;
rdf:source <http://www.abc.com/~jdoe/what-I-know.rdf> ;
rdf:scope dilusions ;
rdf:authentication <esl:SHA1:i8...a82> .
and the triple <s,p.o> is just a resource-centric view of that knowledge
derived from the qualified statement, as Graham points out.
All statements are "reified", per se. Assertion is taken to be an issue
of relevance to any given process -- and selection of relevant statements
is based on a statement's qualification properties. I.e. assertion is
a preliminary query on the statements in a knowledge base to select
knowledge of relevance to a subsequent query or operation.
C.f.
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Nov/0303.htmlhttp://www-nrc.nokia.com/sw/draft-pstickler-auth-00.html
Of course, changes of a magnitude such as suggested above are totally
beyond the scope of the present charter, which is why I dropped discussion
of the X proposal (for now ;-)
Cheers,
Patrick
--
Patrick Stickler Phone: +358 50 483 9453
Senior Research Scientist Fax: +358 7180 35409
Nokia Research Center Email: patrick.stickler@nokia.com